Measuring Sustainability in Residential Buildings

We get a lot of people asking us for a basic overview of what tools are available to measure sustainability performance and outcomes in buildings. Here is an overview of the main ‘Green Tools of the Trade’ for Green residential buildings in Australia.

Thankfully, measuring sustainability is becoming easier. There are now a number of ‘tools’ available on the market that will help you measure the sustainability credentials of your residential building project. The most common ones for Australia include NatHERS (6-Star BCA Code), Life Cycle Assessment (LCA) and Green Building Council of Australia’s (GBCA) ‘Green Star’ rating. Additional methods are available to test for heat/gain loss of a building. Models such as the One Planet Living Model and the Living Building Challenge really raise the bar for sustainable development.

NatHERS (6-Star)

The Nationwide House Energy Rating Scheme (NatHERS) applies to the residential sector; it is a national framework that regulates how Australian homes are rated for their thermal performance. NatHERS tools provide a method of demonstrating compliance with the minimum energy efficiency standards for new residential buildings outlined under the National Construction Code (NCC). The focus is on good design and construction which can reduce the operational costs and environment impacts associated with heating and cooling of a home. A minimum 6-Star performance standard became effective in West Australia on 1st May 2011; it is a minimum regulation which is intended to eliminate worst practice. The software is also a powerful tool for optimising energy efficient house designs for Australian climates. NatHERS accredited software includes Accurate Sustainability, BERS Professional, and FirstRate.

Life Cycle Assessment (LCA)

Life Cycle Assessment (LCA) is used to quantify the total “Embodied Energy” and the “Operational Energy” over the entire design life of the building. LCA looks beyond just thermal performance loads – the heating and cooling requirements of a home – and takes into account the impact of a building during its whole life cycle instead. Life Cycle Assessment evolved from the 1960s and is now defined with an International Standard, meaning that there are strict rules about how it is to be applied and relied upon. The standard is available at: AS/NZA ISO 14044:2006.

To achieve the best outcomes, it is recommended to engage a Life Cycle engineer early in the design process and help accurately quantify, compare, improve and certify the environmental performance of your building. It is an affordable and scientifically rigorous way to improve buidings and other forms of infrastructure. Perth based eTool®LCD is one of the few companies operating in this space.

GBCA Green Star

Green Star is a voluntary sustainability rating system for buildings in Australia. It was launched in 2003 by the Green Building Council of Australia (GBCA). The rating tool can be used for buildings, fit outs and community design; due to its costs this tool is mostly used by the commercial sector. Green Star independently assesses project by awarding points in nine categories: Management; Indoor Environment Quality; Energy; Transport; Water; Materials; Land Use & Ecology; Emissions and Innovation. Green star ratings are from 1 to 6 Green Star, with 6 being World Leadership. Performance ratings have to be re-certified every three years to make sure the building’s operations are up to date and to encourage improvement over time. The Green Star rating has helped lift the bar of sustainability outcomes in the built form.

NOTE: Additional ways to measure heat loss/gain

According to Your Home, ‘sealing your home against air leakage is one of the simplest upgrades you can undertake to increase your comfort while reducing your energy bills and carbon emissions by up to 25%’. Both insulation and air tightness are often difficult to inspect with the eye when a building is completed. Additional tests that can be conducted include a blower door test and thermal imaging; both help identify hotspots for heat loss/gain. A blower door test assesses the air tightness of the building; thermal imaging is used to inspect insulation of a building. In Europe, air leakage tests are mandatory in a number of jurisdictions including Sweden and the UK.

International Models for Best Practice

One Planet Living Model

The One Planet Living model is inspired by the UK’s first large-scale mixed use sustainable community: BedZED in London. One Planet Living is a vision for a world where it is easy, attractive, and affordable for people to lead happy and healthy lives with a fair share of the earth’s resources. It uses 10 principles as a holistic framework that provides guidance for local government, businesses and the built environment to comprehensively address key sustainability issues and effectively make a sustainable lifestyle a reality. The 10 principles include: zero carbon, zero waste, sustainable transport, sustainable materials sustainable food, sustainable water, land use and wild life, culture and community, equity and local economy, and health and happiness.

The Ultimate: Living Building Challenge

Currently there are only five ‘living buildings’ in the world. The Living Building Challenge is by far the most advanced and demanding measure of sustainability in the built environment possible today. It is a building certification program, advocacy tool and philosophy. It is comprised on seven performance categories called ‘petals’: Place, Water, Energy, Health & Happiness, Materials, Equity and Beauty. Examples of prerequisites include generating all energy with renewable resources; capturing and treating all water used in the building; and using building materials void of hazardous chemicals. Certification during the design stage is not an option; buildings need to prove that they meet all of the program requirements after 12 months of continued operations and full occupancy.

2 thoughts on “Measuring Sustainability in Residential Buildings”

Hello Anne, apologies in delay responding to you. For some reason we did not get notifications for comments and questions on our website till now so my response my no longer be relevant. Nevertheless, for the blower door test, the guys at Passiv Hause can probably tell you who can do a blower door test in Perth. Their address is http://passivehouse.com.au/page/blower-door-testing. The other group to call would be https://airleak.com.au. It seems you can hire thermal imaging equipment from Kennards. Another organisation operating in this space is http://metrothermalimaging.com.au/
The Green Gurus Team.